1. (Industrial Useful Field)
This invention relates to a clutch of the so-called pull type which performs release operation by pulling a release bearing toward a speed change gear by means of a release lever connected to a clutch pedal.
2. (Prior Art)
In a typical prior-art arrangement of this sort, as FIG. 4 shows, an inclined coil spring 100 is employed as a load generating member which acts on a retainer 102 to cause it to transmit the biasing force of the spring 100 to a pressure plate 106 through a lever 104 so that the pressure plate 106 is pressed against a clutch disk 108 (Japanese Patent Publication No. 46-15046).
However, such arrangement has a drawback that the biasing force of the coil spring 100 causes the pedal effort to increase as the stroke of the clutch pedal becomes greater, so that the pedal effort is increased during clutch release operation.
Another problem is that during high-speed operation the coil spring 100 is compressed under centrifugal force acting thereon, with the result that the spring force acting on the pressure plate 106 is reduced.
The present applicant developed a clutch which could eliminate these drawbacks of such pull-type clutch and already applied for a patent thereon in Japan (Japanese Patent Application No. 66-194158, filed on Sept. 2, 1985).
In this prior-art arrangement, as FIG. 5 shows, a diaphragm spring 110 is employed which is supported by a clutch cover 116 through wire rings 112 and stud pins 114. One difficulty with this clutch is that it is rather troublesome to dismantle the diaphragm spring 110 for replacement. Another difficulty is that a larger number of parts are involved.
3. (Object of the Invention)
Accordingly, it is the object of this invention to provide a pull-type clutch which permits easy dismantling and replacement of the diaphragm spring and which can minimize the number of parts required.
In order to accomplish this object, the clutch in accordance with the invention comprises clutch discs splinedly fitted on an input shaft of a speed change gear, a sleeve fitted over the outer periphery of the input shaft, a release bearing fixed to the sleeve at its end nearer to the speed change gear, a load transmission retainer fitted on the sleeve at its end nearer to a flywheel, the retainer being stopped against dislocation from the sleeve, a clutch cover for covering a pressure plate connected to the flywheel for pressing the clutch discs against the flywheel, a generally disc-shaped spring member disposed between the clutch cover and the retainer, the circumferential edge portion of the spring member being held in position by a holder portion provided on the inner periphery of the clutch cover, the inner peripheral portion of the spring member being pressed against said retainer at its end nearer to the speed change gear, levers disposed between the retainer and the pressure plate, the levers each being supported at a radially inner side fulcrum thereof by the retainer and biased at a radially outer side fulcrum thereof toward the clutch cover, the levers each being biased at an intermediate fulcrum thereof against the pressure plate, so that the load of the spring member acting on the retainer is magnified for transmission at a specified lever ratio between the individual fulcrums of each of the levers.